KR20210128457A - Non-woven laminates and hygiene products - Google Patents

Abstract

A nonwoven fabric layer A comprising crimped composite fibers and a nonwoven fabric layer B comprising ultrafine fibers having an average fiber diameter of less than 1.35 μm, wherein the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 2.0% to 8.0 % of nonwoven laminates and hygiene products.

Description

Non-woven laminates and hygiene products

The present disclosure relates to nonwoven laminates and hygiene products.

Since the nonwoven fabric using polyolefin (for example, polypropylene) is excellent in air permeability, etc., although it is used as hygiene materials, such as a paper diaper and a sanitary product, further improvement of the characteristic is calculated|required. For example, there is a demand for a nonwoven fabric using polypropylene with further improved flexibility, bulkiness, and mechanical strength.

As a method of obtaining a nonwoven fabric having excellent flexibility, bulkiness, and the like, various methods have been proposed in which fibers using polyolefin constituting the nonwoven fabric are crimped.

) 구조를 갖는 복합 섬유로 한 경우에, 초부에 이용하는 저융점의 프로필렌계 중합체보다 Mz/Mw가 큰 고융점의 프로필렌계 중합체를 심부에 이용하여 복합 섬유로 하면, 보다 고도로 권축된 권축 복합 섬유가 얻어짐이 기재되어 있다.For example, in patent document 1, the eccentric core sheath using two types of propylene polymers from which melting|fusing point differs

) when a composite fiber having a structure obtained is described.

In addition, Patent Document 2 and Patent Document 3 describe a composite in which meltblown fibers are laminated on an intermediate layer of a crimped composite fiber laminate.

International Publication No. 2011-129211 Specification of US Patent Application Publication No. 2017/0335498 International Publication No. 2017/198336

The composite fiber described in Patent Document 1 is concerned that the neck-in at the time of processing becomes large, and it is considered that there is a problem in stable production at the time of high-speed molding.

On the other hand, in the present disclosure, neck-in means, for example, when the nonwoven fabric is stretched in the MD direction (fiber flow direction), the length of the nonwoven fabric in the CD direction (direction orthogonal to the fiber flow direction) by stretching the fibers. means the shortening of

The composite described in Patent Document 2 and Patent Document 3 has a large fiber diameter and basis weight of the meltblown layer introduced as an intermediate layer, and thus it is considered that the bending rigidity is relatively high. Therefore, it is estimated that the softness|flexibility (for example, cushioning property, drape property, etc.) of the nonwoven fabric laminated body itself which becomes important especially in a hygiene product, and a neck toughness may be inferior.

A problem to be solved by the embodiments of the present disclosure is to provide a nonwoven fabric laminate and a hygiene product that exhibits good flexibility due to low bending rigidity and is excellent in neck toughness.

The following aspects are included in the means for solving the said subject.

<1> A nonwoven fabric layer A comprising crimped composite fibers and a nonwoven fabric layer B comprising ultrafine fibers having an average fiber diameter of less than 1.35 μm, wherein the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 2.0 % to 8.0% of the nonwoven fabric laminate.

<2> The nonwoven fabric laminate according to <1>, wherein the ultrafine fibers have an average fiber diameter of 1.00 µm or more and less than 1.35 µm.

<3> The nonwoven fabric laminate according to <1> or <2>, wherein the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 5.0% to 8.0%.

<4> The nonwoven fabric laminate according to any one of <1> to <3>, wherein the nonwoven fabric layer A is a layer of a spunbond nonwoven fabric, and the nonwoven fabric layer B is a layer of a meltblown nonwoven fabric.

<5> The crimped conjugated fiber has at least two regions, a part (a) composed of the olefin-based polymer (A) and a part (b) composed of the olefin-based polymer (B), and the part (a) and the mass ratio [(a):(b)] of the part (b) is 10:90 to 60:40, and the melting point of the olefin-based polymer (A) is higher than the melting point of the olefin-based polymer (B), and The nonwoven fabric laminate according to any one of <1> to <4>, wherein Mz/Mw of the olefin-based polymer (A) is larger than Mz/Mw of the olefin-based polymer (B).

<6> The nonwoven fabric laminate according to <5>, wherein the olefin-based polymer (A) and the olefin-based polymer (B) are propylene-based polymers.

<7> The nonwoven fabric laminate according to <5> or <6>, wherein the crimped composite fiber has an eccentric core-sheath structure in which the (a) part is a core part (a') and the (b) part is a sheath part (b').

<8> The nonwoven fabric laminate according to any one of <1> to <7>, which is heat-sealed by embossing.

<9> The nonwoven fabric laminate according to <8>, wherein the embossed area ratio by the embossing is 5% to 20%.

<10> A hygiene product having the nonwoven fabric laminate according to any one of <1> to <9>.

ADVANTAGE OF THE INVENTION According to embodiment of this indication, the nonwoven fabric laminated body which shows favorable softness|flexibility and is excellent in neck toughness and hygiene product by suppressing bending rigidity low can be provided.

1 is a perspective view showing an example of a crimped composite fiber of the present disclosure.
2 is a view for explaining a method for testing the flexibility of a nonwoven fabric.
3 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
4 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
5 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
6 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
7 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
8 is a cross-sectional view showing an example of the crimped composite fiber of the present disclosure.
It is a schematic diagram which shows an example of the spunbonded nonwoven fabric manufacturing apparatus in this indication.

Hereinafter, although the nonwoven fabric laminated body and hygiene product of this indication are demonstrated in detail, this indication is not limited at all to the following embodiment, Within the scope of the objective of this indication, it can implement with appropriate change. .

In the present disclosure, the numerical range indicated using "-" means a range including the numerical values described before and after "-" as the lower limit and the upper limit. In the numerical range described step by step in the present disclosure, the upper limit or lower limit described in any numerical range may be substituted with the upper limit or lower limit of the numerical range described in other steps. In addition, in the numerical range described in this indication, the upper limit or lower limit described in a certain numerical range may be substituted with the value shown in the Example.

In the present disclosure, the term "process" is included in this term as long as the purpose of the process is achieved not only as an independent process, but also when it cannot be clearly distinguished from other processes.

In the present disclosure, the content of each component in the composition means the total amount of the plurality of substances present in the composition, unless otherwise specified, when a plurality of types of substances corresponding to each component exist in the composition.

In this indication, "MD" (Machine Direction) direction points out the advancing direction of the nonwoven web in a nonwoven fabric manufacturing apparatus. A "CD" (Cross Direction) direction refers to a direction perpendicular to the MD direction and parallel to a main surface (plane orthogonal to the thickness direction of the nonwoven fabric).

In the present disclosure, when referring to the amount of each component in the composition, when a plurality of substances corresponding to each component exist in the composition, unless otherwise specified, it means the total amount of the plurality of substances present in the composition .

In the present disclosure, the term "layer" includes a case in which the layer is formed in only a part of the region in addition to the case in which the entire region is formed when the region in which the layer is present is observed.

≪Non-woven fabric laminate≫

The nonwoven fabric laminate of the present disclosure includes a nonwoven fabric layer A comprising crimped composite fibers and a nonwoven fabric layer B comprising ultrafine fibers having an average fiber diameter of less than 1.35 μm, and the basis weight of the nonwoven fabric layer B relative to the total basis weight of the nonwoven fabric laminate ratio is 2.0% to 8.0%.

The laminated body using only the nonwoven fabric layer containing the crimped conjugated fibers had a large neck-in shrinkage width, and therefore had a tendency to be inferior in neck toughness resistance.

In addition, the nonwoven fabric layer B containing the ultrafine fibers can improve the neck toughness, but increase the bending rigidity, which can be a factor of lowering the flexibility.

The nonwoven fabric laminate of the present disclosure exhibits good flexibility by suppressing bending rigidity low by having the above configuration, and is excellent in neck toughness.

The ultrafine fibers are thinner than the crimped composite fibers. Therefore, in the nonwoven fabric laminate, the ultrafine fibers can be more uniformly dispersed as compared to the crimped composite fibers.

In addition, since the ultrafine fibers can contribute to maintaining the shape of the nonwoven fabric laminate, the inclusion of the ultrafine fibers in the nonwoven fabric laminate prevents the contraction in the longitudinal and transverse directions (that is, the neck-in phenomenon) when the nonwoven fabric laminate is stretched in the transverse longitudinal direction. It is presumed that

On the other hand, "flexibility" in the present disclosure means the flexibility of the nonwoven fabric laminate itself due to low bending rigidity and excellent drape properties.

<Nonwoven fabric layer A containing crimped composite fibers>

The nonwoven fabric laminate of the present disclosure includes a nonwoven fabric layer A containing crimped composite fibers.

When the nonwoven fabric laminate of the present disclosure includes the nonwoven fabric layer A containing crimped conjugated fibers, the bending rigidity of the nonwoven fabric laminate can be reduced and flexibility can be improved.

The crimped composite fiber is preferably a spunbond fiber produced by the spunbonding method from the viewpoint of improving the flexibility by reducing the bending rigidity of the nonwoven fabric laminate.

Nonwoven fabric layer A, in addition to crimped composite fibers, includes spunbond nonwoven fabric, card type air through nonwoven fabric, air laid nonwoven fabric, needle punch type spunbond nonwoven fabric, wetted nonwoven fabric, dry nonwoven fabric, dry pulp nonwoven fabric, flash spinning nonwoven fabric, open fiber nonwoven fabric, and various other nonwoven fabrics. Although a well-known nonwoven fabric etc. may be included, it is preferable that only crimped composite fiber is included.

The crimped composite fiber can be formed, for example, when the composite fiber has a crimpable cross-sectional shape.

The said crimped conjugated fiber may be comprised from several types of polymers by the spun bonding method, An olefin type polymer, a polyester type polymer, nylon, etc. are mentioned as said polymer.

Among the above, it is preferable that the said polymer is an olefinic polymer from a viewpoint of the flexibility, strength, and water resistance of the nonwoven fabric laminate itself.

The crimped conjugated fiber in the present disclosure may have at least two regions, for example, part (a) composed of a specific polymer and part (b) composed of another polymer different from the specific polymer. .

In addition, the crimped conjugated fiber in the nonwoven fabric laminate of the present disclosure has at least two regions: part (a) composed of the olefin-based polymer (A) and part (b) composed of the olefin-based polymer (B). it is preferable

(Olefin polymer (A))

Examples of the olefin-based polymer (A) include an ethylene-based polymer and a propylene-based polymer. Among the above, it is preferable that it is a propylene-type polymer as an olefin-type polymer (A).

In addition, the olefin polymer (A) may be comprised from one type of polymer, and two or more types of polymers, ie, a mixture of two or more types of polymers may be sufficient as it.

An ethylene polymer is a polymer mainly having a structural unit derived from ethylene, and is a concept containing ethylene homopolymer and the copolymer of ethylene and alpha-olefin other than ethylene.

For example, either an ethylene homopolymer or a copolymer of ethylene and an ?-olefin other than ethylene (ethylene/?-olefin random copolymer) may be used.

The ethylene/α-olefin random copolymer is, for example, preferably a random copolymer of ethylene and one or two or more α-olefins having 2 to 10 carbon atoms other than ethylene.

Specific examples of the α-olefin copolymerized with ethylene from the viewpoint of excellent flexibility include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, and 3-methyl -1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and the like.

Examples of the ethylene/α-olefin random copolymer include an ethylene/propylene random copolymer and an ethylene/1-butene random copolymer.

The ethylene polymer may contain 2 or more types of different ethylene polymers.

The propylene-based polymer used as the olefin-based polymer (A) is a polymer mainly composed of structural units derived from propylene, and is a propylene homopolymer and a copolymer of propylene and an α-olefin other than propylene (propylene/α-olefin random copolymer). ) is a concept that includes

For example, the propylene-based polymer may be a propylene homopolymer, a copolymer of propylene and an α-olefin other than propylene, a propylene homopolymer, and a copolymer of propylene and an α-olefin other than propylene. there may be

The propylene/α-olefin random copolymer is preferably a random copolymer of propylene and one or two or more α-olefins having 2 to 10 carbon atoms other than propylene.

Preferred specific examples of the α-olefin copolymerized with propylene from the viewpoint of excellent flexibility include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 3- methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene, and the like.

Examples of the propylene/α-olefin random copolymer include a propylene/ethylene random copolymer and a propylene/ethylene/1-butene random copolymer.

The content of α-olefin in the propylene/α-olefin random copolymer is not particularly limited, and for example, is preferably 10 mol% or less, more preferably 5 mol% or less, and still more preferably 2 mol% or less. and 1 mol% or less is particularly preferred.

A propylene-type polymer may contain 2 or more types of different propylene-type polymers, and may also contain a propylene-type polymer and an ethylene-type polymer.

Among the above, from the viewpoint of excellent mechanical strength, the olefin-based polymer (A) is preferably a homopolymer of propylene.

The melt flow rate (MFR) (ASTMD-1238, 230°C, load 2,160 g) of the olefin polymer (A) is preferably 20 g/10 min to 100 g/10 min from the viewpoint of spinnability, and 30 g/10 min to It is more preferable that it is 80 g/10min.

On the other hand, when MFR is 100 g/10min or less, the tensile strength of the nonwoven fabric laminated body obtained, etc. can be improved.

The olefin-based polymer (A) in the present disclosure preferably has a higher melting point than the olefin-based polymer (B), and the difference preferably exceeds 10°C, and the difference is in the range of 12°C to 40°C. It is more preferable to have

By increasing the melting point difference between the olefin-based polymer (A) and the olefin-based polymer (B), it is possible to obtain a crimped composite fiber from a composite fiber having more excellent crimping properties.

It is preferable that melting|fusing point is 155 degreeC or more, and, as for the olefin polymer (A) in this indication, it is more preferable that it is 157 degreeC - 165 degreeC.

When the melting point of the olefin-based polymer (A) is 155°C or higher, it becomes easier to make the difference between the melting point of the olefin-based polymer (A) and the melting point of the olefin-based polymer (B) more than 10°C. A crimped composite fiber can be obtained from the composite fiber excellent in axial property.

The ratio [Mz/Mw(A)] of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) of the olefinic polymer (A) in the present disclosure is preferably 2.0 or more from the viewpoint of exhibiting good crimpability, , it is preferable that Mz/Mw(A) is 4.5 or less from a viewpoint of radioactivity.

From a viewpoint similar to the above, 2.1-4.5 are more preferable, and, as for Mz/Mw(A) of an olefin polymer (A), 2.1-3.0 are still more preferable.

It is preferable that Mw is 150,000-250,000, and, as for the olefin polymer (A) in this indication, it is preferable that Mz is 300,000-600,000.

The olefin-based polymer (A) in the present disclosure preferably has a ratio [Mw/Mn(A)] of a weight average molecular weight (Mw) and a number average molecular weight (Mn) defined as molecular weight distribution of 2.0 to 4.0, 2.2-3.5 are more preferable.

In the present disclosure, Mz, Mw, Mn, Mz/Mw(A) and Mw/Mn(A) of the olefin polymer (A) are measured by the method described later by GPC (gel permeation chromatography). can do.

The olefinic polymer (A) in the present disclosure is usually a Ziegler-Natta catalyst in which a so-called titanium-containing solid-phase transition metal component and an organometallic component are combined, or at least one cyclopentadienyl skeleton in the periodic table 4 Using a metallocene catalyst comprising a transition metal compound of Groups to 6 and a cocatalyst component, slurry polymerization, gas phase polymerization, bulk polymerization, for example, homopolymerization of propylene, or, for example, propylene and a small amount of α - Obtained by copolymerizing an olefin. At that time, a small amount of a propylene-based polymer having a different MFR, particularly a propylene-based polymer having a smaller MFR than the propylene-based polymer, is mixed or multi-staged with a propylene-based polymer having a different MFR so that Mz, Mw and Mz/Mw are within the above ranges. It can be manufactured, and it can obtain also by superposing|polymerizing directly.

In addition, Mw/Mn(A) and Mz/Mw(A) of the olefinic polymer (A) are adjusted by polymerization conditions using a specific catalyst, a method for adjusting the polymer by decomposing it with a peroxide, etc., molecular weight It can be adjusted by the method of mixing and adjusting two or more types of these different polymers, etc.

On the other hand, as the olefin-based polymer (A) in the present disclosure, it is also possible to use a commercially available product, for example, a propylene-based polymer manufactured and sold under the trade name Novatech PP SA06A by Nippon Polypropylene Corporation.

Antioxidants, weathering stabilizers, light stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, pigments, etc. which are normally used for the olefin polymer (A) in this indication, within the range which does not impair the objective of this indication. of additives or other polymers can be blended as needed.

(Olefin polymer (B))

Examples of the olefin-based polymer (B) include an ethylene-based polymer and a propylene-based polymer.

The ethylene polymer in the olefin polymer (B) is the same as the ethylene polymer described in the term of the olefin polymer (A) described above, and the same applies to a preferred embodiment.

The propylene-based polymer in the olefin-based polymer (B) is the same as the propylene-based polymer described in the above-mentioned olefin-based polymer (A), and the same applies to a preferred embodiment.

Moreover, as a propylene-type polymer in an olefin-type polymer (B), the following aspect is also preferable.

The propylene-based polymer used as the olefin-based polymer (B) may be a homopolymer of propylene, and includes propylene and a small amount of one or more α-olefins (provided that propylene is excluded) ) may be a copolymer.

Among the above, from the viewpoint of excellent balance between neck toughness and flexibility, as the propylene polymer used as the olefin polymer (B), a copolymer of propylene and a small amount of one or more α-olefins is more preferable, and among them, propylene A propylene/?-olefin random copolymer such as an ethylene random copolymer or a propylene/ethylene/1-butene random copolymer is more preferable.

The melt flow rate (MFR) (ASTMD-1238, 230°C, load 2,160 g) of the olefin-based polymer (B) is in the same range as the MFR of the above-described olefin-based polymer (A). desirable.

It is preferable that melting|fusing point is 120 degreeC - 155 degreeC, and, as for the olefinic polymer (B), it is more preferable that it exists in the range of 125 degreeC - 150 degreeC.

When melting|fusing point of an olefinic polymer (B) is 120 degreeC or more, heat resistance can be maintained favorably.

The ratio [Mz/Mw(B)] of the Z average molecular weight (Mz) to the weight average molecular weight (Mw) of the olefin polymer (B) is preferably 2.5 or less, and more preferably 2.3 or less.

It is preferable that Mw is 150,000-250,000, and, as for the olefin polymer (B), it is preferable that Mz exists in the range of 300,000-600,000.

The olefin-based polymer (B) preferably has a ratio [Mw/Mn(B)] of a weight average molecular weight (Mw) to a number average molecular weight (Mn) defined as molecular weight distribution of 2.0 to 4.0, in the range of 2.2 to 3.5 It is more preferable to be in

In the present disclosure, Mz, Mw, Mn, Mz/Mw (B) and Mw/Mn (B) of the olefinic polymer (B) are measured by the method described later by GPC (gel permeation chromatography). can do.

The olefin-based polymer (B) in the present disclosure can be produced by the same polymerization method as that of the olefin-based polymer (A). For example, a propylene/α-olefin random copolymer is used as the olefin-based polymer (B). When used, propylene/α-olefin random copolymers having different MFRs may be prepared by mixing or multistage polymerization in small amounts, or may be prepared by direct polymerization so that Mz, Mw and Mz/Mw are within the above ranges.

As a method of adjusting the Mw/Mn(B) and Mz/Mw(B) of the olefinic polymer (B), a method of adjusting according to polymerization conditions using a specific catalyst, a method of adjusting by decomposing the polymer with a peroxide or the like , the method of mixing and adjusting two or more types of polymers from which molecular weight differs, etc. are mentioned.

As the olefin-based polymer (B), it is also possible to use a commercially available product, for example, a propylene-based polymer manufactured and sold under the trade name Prime Polypro S119 from Prime Polymer Co., Ltd.

Antioxidants, weathering stabilizers, light stabilizers, antistatic agents, antifogging agents, antiblocking agents, lubricants, nucleating agents, pigments, etc. which are normally used in the olefinic polymer (B) in this indication in the range which does not impair the objective of this indication. of additives or other polymers can be blended as needed.

From the viewpoint of excellent balance between mechanical strength, neck toughness and flexibility of the resulting nonwoven fabric laminate, the olefin polymer (A) and the olefin polymer (B) are preferably a propylene polymer, and the olefin polymer (A) is a propylene homopolymer, and the olefinic polymer (B) is preferably a propylene/α-olefin random copolymer.

In the present disclosure, the melting point of the olefin-based polymer (A) is higher than the melting point of the olefin-based polymer (B), and Mz/Mw of the olefin-based polymer (A) is Mz of the olefin-based polymer (B) It is preferable to satisfy at least one of those larger than /Mw. Thereby, the crimpability of a crimped composite fiber can be made favorable.

Moreover, it is more preferable that melting|fusing point (Tm), Mz/Mw, and MFR of an olefin type polymer (A) and an olefin type polymer (B) satisfy|fill the following relationship.

<△Tm>

In the present disclosure, the melting point of the olefin-based polymer (A) is preferably higher than the melting point of the olefin-based polymer (B).

Thereby, a crimped composite fiber can be obtained from the composite fiber which is more excellent in crimping property.

The difference between the melting point of the olefinic polymer (A) constituting part (a) of the present disclosure and the melting point of the olefinic polymer (B) constituting part (b) of the present disclosure from the viewpoint of obtaining the crimped composite fiber from the composite fiber having more excellent crimpability It is preferable that it exceeds 10 degreeC, and it is more preferable that the difference is 12 degreeC - 40 degreeC.

Moreover, when melting|fusing point of an olefinic polymer (B) is 155 degrees C or less, it becomes easier to make melting|fusing point difference with an olefinic polymer (A) into a difference exceeding 10 degreeC.

The value of ?Tm is calculated by determining the melting points of the olefin-based polymer (A) and the olefin-based polymer (B) used as raw materials for parts (a) and (b), respectively, and the difference.

In the present disclosure, the melting point is measured as follows.

1) The olefinic polymer is set in a measuring pan for differential scanning calorimetry (DSC) manufactured by Perkin Elmer, and the temperature is raised from 30°C to 200°C at 10°C/min, and maintained at 200°C for 10 minutes, then 30°C The temperature is lowered at 10°C/min until

2) Next, the temperature is again raised from 30°C to 200°C at 10°C/min, and the melting point is determined from the peak observed during that time.

<△Mz/Mw>

In the present disclosure, Mz/Mw of the olefin-based polymer (A) is preferably larger than Mz/Mw of the olefin-based polymer (B).

Thereby, a crimped composite fiber can be obtained from the composite fiber excellent in crimping property.

The difference between Mz/Mw(A) of the olefinic polymer (A) constituting part (a) of the present disclosure and Mz/Mw(B) of the olefinic polymer (B) constituting part (b) of the present disclosure [Mz/Mw(A) )-Mz/Mw(B): ΔMz/Mw] is preferably 0.01 to 2.0, more preferably 0.03 to 1.0, and still more preferably 0.05 to 0.40.

When ΔMz/Mw is 0.01 or more, a crimped composite fiber can be obtained from a composite fiber excellent in crimping properties. On the other hand, when (DELTA)Mz/Mw is 2.0 or less, spinnability can be maintained favorably.

In addition, Mz is called Z average molecular weight, it is well-known, and is defined by the following formula (1).

In formula (1), Mi is the molecular weight of the polymer [Olefin-based polymer (A) and olefin-based polymer (B): hereinafter referred to as "olefin-based polymer" when combined.], Ni is the polymer (olefin-based polymer) is the forfeiture of

Generally, it is thought that Mz is the molecular weight which reflected the high molecular weight component of a polymer more. Therefore, Mz/Mw shows a molecular weight distribution reflecting a higher molecular weight component more than Mw/Mn which is an index|index of a general molecular weight distribution. This value affects the crimpability of the fiber.

ΔMz/Mw is calculated by determining the Mz/Mw of each of the olefin polymer (A) and the olefin polymer (B) constituting the parts (a) and (b) by GPC analysis, and using the absolute value of the difference. do.

In the present disclosure, GPC analysis is performed under the following conditions.

1) 30 mg of propylene polymer is completely dissolved in 20 mL of o-dichlorobenzene at 145°C.

2) The solution is filtered through a sintered filter having a pore size of 1.0 µm, and used as a sample.

3) The sample is analyzed by GPC, converted to polystyrene (PS), and an average molecular weight and molecular weight distribution curve are obtained.

Measuring equipment and measurement conditions are as follows.

Measuring device Gel permeation chromatograph Alliance GPC2000 type (manufactured by Waters)

Analysis device data processing software Empower2 (manufactured by Waters)

Column TSKgel GMH6-HT × 2 + TSKgel GMH6-HTL × 2 (all 7.5 mm I.D. × 30 cm, manufactured by Tosoh Corporation)

Column temperature 140°C

Mobile phase o-dichlorobenzene (containing 0.025% butylated hydroxytoluene BHT)

Detector Differential Refractometer

Flow rate 1mL/min

Sample concentration 30mg/20mL

Injection volume 500 μL

Sampling time interval 1s

Column calibration monodisperse polystyrene (manufactured by Tosoh Corporation)

Molecular weight conversion PS conversion/standard conversion method

<MFR ratio>

The ratio of the MFR of the olefin-based polymer (A) constituting part (a) of the present disclosure to the MFR of the olefin-based polymer (B) constituting part (b) (hereinafter also referred to as “MFR ratio”) is not particularly limited. , it is preferably 0.8 to 1.2.

It is preferable that MFR of the olefin type polymer (A) and olefin type polymer (B) in this indication are 20 g/10min - 100 g/10min.

In the present disclosure, MFR is, according to ASTM D1238, load; 2,160 g and temperature; It is calculated|required at 230 degreeC.

<Mass ratio of part (a) and part (b)>

The mass ratio [(a):(b)] of the part (a) to the part (b) in the crimped composite fiber of the present disclosure is preferably 10:90 to 60:40.

When the mass ratio of the part (a) and the part (b) is within the above range, the crimpability of the composite fiber used for forming the crimped composite fiber can be made better, and the flexibility of the nonwoven fabric laminate can be further improved.

From the above viewpoint, the mass ratio [(a):(b)] of the part (a) to the part (b) is more preferably 10:90 to 50:50, and still more preferably 20:80 to 40:60.

The crimped conjugated fiber in the present disclosure has at least two regions: a part (a) composed of the olefin-based polymer (A) and a part (b) composed of the olefin-based polymer (B), and the part (a) and the mass ratio [(a):(b)] of the part (b) is 10:90 to 60:40, and the olefin-based polymer (A) and the olefin-based polymer (B) have Mz/Mw, melting point and It is preferred that at least one of the MFRs is a different aspect.

In the nonwoven fabric laminate of the present disclosure, the crimped conjugated fibers have at least two regions: a part (a) composed of an olefin-based polymer (A) and a part (b) part composed of the olefin-based polymer (B),

The mass ratio [(a):(b)] of part (a) and part (b) is 10:90 to 60:40,

At least one of the melting point of the olefin-based polymer (A) is higher than the melting point of the olefin-based polymer (B), and the Mz/Mw of the olefin-based polymer (A) is larger than the Mz/Mw of the olefin-based polymer (B). It is preferable to do

The crimped conjugated fiber of the present disclosure is a crimped conjugated fiber composed of the olefinic polymer (A) and the olefinic polymer (B), the crimped conjugated fiber having a cross section of at least two regions (a) and (b) is,

The mass ratio [(a):(b)] of the part (a) to the part (b) is 10:90 to 60:40, the part (a) is an olefinic polymer (A), and the part (b) is each composed of an olefin-based polymer (B), and the difference between Mz/Mw(A) of the olefin-based polymer (A) and Mz/Mw(B) of the olefin-based polymer (B) [Mz/Mw(A)- Mz/Mw(B): ΔMz/Mw] is 0.10 to 2.2, and the melting point [Tm(A)] of the olefinic polymer (A) and the melting point of the olefinic polymer (B) [Tm(B)] A crimped composite fiber having a difference [ΔTm=Tm(A)-Tm(B)] exceeding 10°C may be sufficient.

The average fiber diameter of the crimped composite fibers in the present disclosure is preferably 8 µm or more, and 10 µm or more from the viewpoint of excellent yarn properties, crimping properties, and neck toughness and mechanical strength when a nonwoven fabric laminate is used. It is more preferable, and it is still more preferable that it is 14 micrometers or more.

In addition, the average fiber diameter of the crimped composite fibers in the present disclosure is preferably 23 µm or less, more preferably 20 µm or less, and still more preferably 17 µm or less, from the viewpoint of excellent flexibility of the nonwoven fabric laminate itself when the nonwoven fabric laminate is used. and 16.6 µm or less is particularly preferred.

In addition, in this indication, the average fiber diameter is measured by the method as described in the term of an Example.

1 is a perspective view showing an example of a crimped composite fiber of the present disclosure. In the figure, reference numeral 10 denotes a part (a), and reference numeral 20 denotes a part (b).

In the cross section of the crimped composite fiber in the cross section of the present disclosure in which the cross section has at least two regions (a) and (b), in the cross section of the crimped composite fiber, the ratio occupied by (a) part, (b) part, is As described above, the mass ratio [(a):(b)] is 10:90 to 60:40, preferably 10:90 to 50:50, more preferably 20:80 to 40:60.

The crimped conjugated fiber having such a structure is not particularly limited, and can take various well-known shapes. Specifically, for example, the side-by-side type (parallel type) crimped composite fiber in which the (a) part and (b) part are in contact with each other, or (a) part is a core part (a'), and (b) part is a sheath part The core-sheath crimped composite fiber which consists of (b') is mentioned.

A core-sheath crimped composite fiber consists of a core part and a sheath part, and says the fiber which crimped. The core part (a') is arranged so that at least a part is surrounded by a polymer different from that of the core part (a') in the cross section of the fiber, and it refers to a part extending in the longitudinal direction of the fiber.

The sheath portion (b') refers to a portion arranged to surround at least a part of the core portion (a') in the cross section of the fiber and extending in the longitudinal direction of the fiber. Among the core-sheath crimped composite fibers, those in which the center of the core (a') of the fiber and the center of the sheath (b') are not the same in the cross section of the fiber are crimped composite fibers with an eccentric core-sheath structure (also called eccentric core-sheath crimped composite fibers). called).

～Eccentric Core Sheath Structure～

In the nonwoven fabric laminate of the present disclosure, the crimped composite fiber preferably has an eccentric core-sheath structure in which the (a) part is a core part (a') and the said (b) part is a sheath part (b').

When the crimped composite fiber has the eccentric core-sheath structure, the crimpability of the composite fiber used for formation of the crimped composite fiber can be made better, and the flexibility of the nonwoven fabric laminate can be further improved.

The eccentric core-sheath structure is, for example, (a) composed of an olefinic polymer (A) having a larger Mz/Mw as a core, and (b) composed of an olefinic polymer (B) having a smaller Mz/Mw Wealth can be used as a starting point.

The eccentric core-sheath crimped composite fiber includes an "exposed type" in which the side surface of the core portion (a') is exposed and an "unexposed type" in which the side surface of the core portion a' is not exposed.

The eccentric core-sheath crimped composite fiber is preferably an exposed eccentric core-sheath crimped composite fiber. This is because an eccentric core-sheath type crimped composite fiber having excellent crimping properties can be obtained. In addition, the cross section of the core part a' and the sheath part b' may be a straight line or a curve may be sufficient as it, and circular, an ellipse, or a square may be sufficient as the cross section of a core part.

The composite fiber in which the joint surface of the core part and the sheath part is straight, and a part of the core part is exposed on the surface of a crimped composite fiber is also called a side-by-side type.

3 to 8 show other examples of cross-sectional views of the crimped composite fiber according to the present disclosure.

As a method for producing the crimped composite fiber, a known method can be used. For example, in the nonwoven fabric manufacturing apparatus shown in FIG. 9, when spinning the raw material extruded from the extruders 1 and 1' for extruding the raw material, the aspect of the crimped composite fiber such as the core-sheath type crimped composite fiber described above can form.

The crimped conjugated fibers of the present disclosure may be short fibers or long fibers, but long fibers are preferable because the crimped conjugated fibers do not fall off from the nonwoven fabric and have excellent fluff resistance when the nonwoven fabric is used. The number of crimps of the crimped composite fiber is not particularly limited, and examples thereof include 5 pieces/25 mm or more. It is preferable that it is 20 pieces/25 mm or more, and, as for the number of crimps, it is more preferable that it is 25 pieces/25 mm or more from a viewpoint of making it bulky and set it as the spunbonded nonwoven fabric excellent in flexibility.

Examples of the nonwoven fabric using the crimped composite fiber include a crimped spunbond nonwoven fabric that is crimped by causing distortion in the fiber during cooling. Currently, as long fibers of crimped spunbond nonwoven fabrics, eccentric core-sheath composite long fibers, parallel type (side-by- side type) composite long fibers, eccentric hollow composite long fibers, and the like.

<Nonwoven fabric layer B containing ultrafine fibers>

The nonwoven fabric laminate of the present disclosure includes a nonwoven fabric layer B containing ultrafine fibers having an average fiber diameter of less than 1.35 μm.

When the nonwoven fabric laminate of the present disclosure includes the nonwoven fabric layer B, the neck toughness of the nonwoven fabric laminate can be improved.

From the viewpoint of further improving the neck toughness of the nonwoven fabric laminate, the ultrafine fibers are preferably meltblown nonwoven fabrics produced by the meltblown method.

Nonwoven fabric layer B, in addition to ultrafine fibers, includes meltblown nonwoven fabric, card air-through nonwoven fabric, air-laid nonwoven fabric, needle punch spunbond nonwoven fabric, wet nonwoven fabric, dry nonwoven fabric, dry pulp nonwoven fabric, flash spinning nonwoven fabric, open fiber nonwoven fabric, and various known nonwoven fabrics. nonwoven fabric or the like may be included, but it is preferable to include only ultrafine fibers.

In the nonwoven fabric laminate of the present disclosure, the average fiber diameter of the ultrafine fibers is less than 1.35 µm.

Thereby, it becomes a laminated body excellent in uniformity and good bonding (texture), and a nonwoven fabric laminated body excellent in neck toughness can be obtained.

From a viewpoint similar to the above, it is preferable that the average fiber diameter of the ultrafine fibers is 1.34 µm or less.

In addition, the average fiber diameter of the ultrafine fibers is preferably 1.00 µm or more from the viewpoint of obtaining a nonwoven fabric laminate having high single yarn strength and exhibiting sufficient mechanical properties.

In addition to obtaining a nonwoven fabric laminate exhibiting sufficient mechanical properties, it is more preferably 1.20 µm or more, and 1.30 µm or more from the viewpoint of obtaining a laminate having excellent uniformity and good formation, and obtaining a laminate of nonwoven fabric excellent in neck toughness. It is more preferably not less than μm.

The method for measuring the average fiber diameter of the ultrafine fibers is as described in the section of Examples.

The ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 2.0% to 8.0%.

When the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 2.0% or more, a laminate excellent in uniformity and good formation is obtained, and a nonwoven fabric laminate excellent in neck toughness can be obtained.

From a viewpoint similar to the above, the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is preferably 5.0% or more, more preferably 6.0% or more, and still more preferably 6.3% or more.

When the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 8.0% or less, a nonwoven fabric laminate having low bending rigidity and excellent flexibility of the nonwoven fabric laminate itself can be obtained.

From a viewpoint similar to the above, the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is preferably 8.0% or less, more preferably 7.0% or less, and still more preferably 6.8% or less.

In addition, the "neck-in coefficient" in this indication is a value computed by ^{width retention (%) / basis weight (g/m<2>).}

In addition, "width retention (%)" and "basis weight (g/m ² )" are values computed by the method as described in the term of an Example.

In the present disclosure, "the ratio of the basis weight of the ultrafine fibers to the total basis weight of the laminate" is a value calculated by ^{the basis weight of the nonwoven fabric layer B (g/m 2} )/the basis weight of the nonwoven fabric laminate (g/m ^{2 )} .

The measuring method of width retention is as having described in the term of an Example.

(water pressure resistance)

In the nonwoven fabric laminate of the present disclosure, it is known that there is a positive correlation between the value of the water pressure resistance and the basis weight of the ultrafine fibers. Therefore, it is possible to estimate the basis weight of the ultrafine fibers from the value of the water pressure resistance.

Thereby, the basis weight ratio of the nonwoven fabric layer B can be estimated using the basis weight of the ultrafine fibers estimated from the value of the water pressure resistance.

The conversion formula for estimating the basis weight of the ultrafine fibers from the value of the water pressure resistance is expressed by the following formula (1).

In addition, Formula 1 is an expression computed from the data of the SMS nonwoven fabric laminated body in the experimental example of International Publication No. 2017/198336, and the experimental example in this indication.

Water pressure resistance [mmH ₂ O] = 55.7 × basis weight of ultrafine fibers [g/m ² ] + 97.0 Formula 1

The ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate can be calculated using the basis weight of the ultrafine fibers estimated from the value of the water pressure resistance using the above conversion formula.

As a material constituting the ultrafine fibers, various known thermoplastic resins, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene , 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene α-olefin homo or copolymer high-pressure method low-density polyethylene, linear low-density polyethylene ( so-called LLDPE), high density polyethylene, propylene polymers (propylene homopolymer, polypropylene random copolymer, propylene/α-olefin copolymer, etc.), poly1-butene, poly4-methyl-1-pentene, ethylene/propylene random copolymer olefinic polymers such as a copolymer, an ethylene-1-butene random copolymer, and a propylene-1-butene random copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide-based polymers such as nylon-6, nylon-66, and polymethylylene adipamide; polyvinyl chloride, polyimide, ethylene/vinyl acetate copolymer, polyacrylonitrile, polycarbonate, polystyrene, ionomer, thermoplastic polyurethane, or mixtures thereof, etc. can be illustrated.

Among the above, the material constituting the ultrafine fibers is preferably an olefin-based polymer, and more preferably a propylene-based polymer.

<Propylene-based polymer>

The ultrafine fibers are preferably propylene polymers from the viewpoint of chemical resistance among the olefin polymers.

As such a propylene-based polymer, a homopolymer of propylene having a melting point (Tm) of 155°C or higher, preferably in the range of 157°C to 165°C, and propylene and one or two or more α-olefins having 2 or more carbon atoms (propylene It is preferable that it is a propylene/alpha-olefin copolymer which is a copolymer of ).

As one or two or more α-olefins (excluding propylene) having 2 or more carbon atoms, one or more α-olefins having 2 to 10 carbon atoms (eg, ethylene, 1-butene, 1-pentene, 1 -Hexene, 1-octene, 1-decene, 3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4-methyl-1-pentene, 4-methyl-1-hexene etc.) are preferable, and 1 type or 2 or more types of alpha-olefins having 2 to 8 carbon atoms are more preferable. Among these, a propylene homopolymer is more preferable. The content of the structural unit derived from the α-olefin of the propylene/α-olefin copolymer is preferably 0.5% by mass to 25% by mass, more preferably 1.0% by mass to 20% by mass, based on all the structural units. .

As long as the propylene polymer can be melt-spun, the melt flow rate (MFR: ASTM D1238, 230° C., load 2,160 g) is not particularly limited, but may be, for example, 1 g/10 min to 3,000 g/10 min. , preferably 500 g/10 min to 2,000 g/10 min, and more preferably 700 g/10 min to 1,600 g/10 min.

In the nonwoven fabric laminate of the present disclosure, non-woven fabric having a basis weight of layer B is more preferably in the range of 0.5g / m ² ~1.5g / m is preferably in the range of ² and 0.7g / m ² ~1.5g / m ² do. As the basis weight of the nonwoven fabric layer B being ^{0.5g / m 2 ~1.5g / m 2} , excellent balance of toughness and flexibility and naenek, it is possible to obtain a thin crimped non-woven fabric.

In addition, the measuring method of the basis weight in this indication is as having described in the term of an Example.

(Neck-in coefficient)

The nonwoven fabric laminate of the present disclosure has a neck-in coefficient of 5.0 or more when stretched at 100 N/m.

When the neck-in coefficient of the nonwoven fabric laminated body of this indication is 5.0 or more, the basis weight of a nonwoven fabric laminated body can be suppressed and the neck-in phenomenon can be suppressed favorably.

From a viewpoint similar to the above, it is preferable that it is 5.2 or more, and, as for the nonwoven fabric laminated body, it is more preferable that it is 5.4 or more of a neck-in coefficient at the time of extending|stretching at 100 N/m.

On the other hand, as a method of adjusting a neck-in coefficient, the following method is mentioned, for example.

A method for adjusting a neck-in coefficient by selecting a resin included in the crimped composite fiber and the ultrafine fiber having an appropriate unit structure and a bonding pattern of the unit structure.

A method of adjusting the neck-in coefficient by selecting a resin having appropriate physical properties (eg, molecular weight distribution, crystallinity, etc.) as the resin contained in the crimped composite fiber and the ultrafine fiber.

The method of adjusting the neck-in coefficient by changing the basis weight ratio of each layer in a laminated body.

In the nonwoven fabric laminate of the present disclosure, it is preferable that the nonwoven fabric layer A is a layer of a spunbonded nonwoven fabric, and the nonwoven fabric layer B is a layer of a meltblown nonwoven fabric.

(Layer containing other fibers)

The nonwoven fabric laminate of the present disclosure may include a layer containing other fibers in addition to the nonwoven fabric layer A and the nonwoven fabric layer B described above.

As a layer containing other fibers, a layer containing a spunbond nonwoven fabric that does not correspond to the nonwoven fabric layer A, a layer containing a meltblown nonwoven fabric not corresponding to the nonwoven fabric layer B, a layer containing a wet-laid nonwoven fabric, and a dry nonwoven fabric layer, a layer containing a dry pulp nonwoven fabric, a layer containing a flash spinning nonwoven fabric, a layer containing an opened nonwoven fabric, and the like, and a layer containing various known nonwoven fabrics.

Among the above, from the viewpoint of maintaining the cushioning properties and flexibility required for recent hygiene materials at a high level while improving the neck toughness, the layer containing other fibers contains a meltblown nonwoven fabric that does not correspond to the nonwoven fabric layer B. It is preferably a layer.

(Basic weight of nonwoven fabric laminate)

The basis weight of the nonwoven fabric laminate of the present disclosure (mass per unit area of the nonwoven fabric laminate unit) is, from the viewpoint of suppressing the phenomenon nekin 8g / m ² ~25g / m ² is desirable, ^{and, 10g / m 2 ~23g / m} 2 it is desirable, ^{and, 12g / m 2 ~18g / m} 2 in that the more preferable, ^{and, 12g / m 2 ~15g / m} 2 more is particularly preferred.

It is preferable that the nonwoven fabric laminated body of this indication is heat-sealed by embossing.

Nonwoven fabric laminate When the crimped composite fibers are heat-sealed to each other by embossing, the stability and strength of the fibers can be maintained well.

It is preferable that the embossing area ratio by the said embossing is 5 to 20% of the nonwoven fabric laminated body of this indication. If it is the said range, the mechanical strength and softness|flexibility required for a sanitary material can be made compatible.

From a viewpoint similar to the above, it is more preferable that the embossing area ratio of embossing is 7 % - 15 %.

About the method of embossing, a well-known method can be used, For example, you may use the method of Unexamined-Japanese-Patent No. 2017-153901.

<Use of nonwoven fabric laminate, etc.>

The nonwoven fabric laminate of the present disclosure can be applied to various uses by being laminated with various layers.

Specifically, for example, a knitted fabric, a woven fabric, a nonwoven fabric, a film, a hygiene product, etc. are mentioned. Among the above, since the nonwoven fabric laminate of the present disclosure exhibits good cushioning properties, flexibility and neck resistance, it is preferable that the nonwoven fabric laminate be used as a hygiene product having the nonwoven fabric laminate of the present disclosure.

In the present disclosure, when laminating (bonding) a layer containing a nonwoven fabric layer A containing crimped composite fibers, a nonwoven fabric layer B containing ultrafine fibers, and other fibers included as needed, embossing, ultrasonic Various known methods can be employed, including thermal fusion methods such as fusion bonding, mechanical entanglement methods such as needle punches and water jets, methods using adhesives such as hot melt adhesives and urethane adhesives, and extrusion lamination.

(Aspect of the nonwoven fabric laminate)

Preferred embodiments of the nonwoven fabric laminate of the present disclosure include a spunbonded nonwoven fabric (crimped) made of crimped composite fibers produced by the spunbonding method, and a meltblown nonwoven fabric (ultrafine fiber) made of meltblown fibers, and other laminated as necessary. A laminate of a nonwoven fabric is mentioned.

Specifically, spunbond nonwoven fabric (crimped)/meltblown nonwoven fabric (extra-fine fibers)/spunbond nonwoven fabric (crimped)/spunbond nonwoven fabric (crimped), spunbond nonwoven fabric (non-crimped)/meltblown nonwoven fabric (extra-fine fibers)/spun Bonded nonwoven fabric (crimped)/spunbond nonwoven fabric (crimped), spunbond nonwoven fabric (non-crimped)/meltblown nonwoven fabric (extra-fine fiber)/spunbond nonwoven fabric (non-crimped)/spunbond nonwoven fabric (crimped) sifter;

Spunbond nonwoven fabric (crimped)/meltblown nonwoven fabric (extra-fine fiber)/spunbond nonwoven fabric (crimped), spunbond nonwoven fabric (non-crimped)/meltblown nonwoven fabric (extra-fine fiber)/spunbond nonwoven fabric (crimped) laminate;

and laminates having a two-layer structure such as meltblown nonwoven fabric (ultrafine fibers)/spunbond nonwoven fabric (crimped).

Among the above, the nonwoven fabric laminate of the present disclosure is preferably a laminate having the three-layer structure and the four-layer structure, more preferably a laminate having a four-layer structure, from the viewpoint of making both the flexibility of the nonwoven fabric laminate and the neck toughness resistance.

In addition, among the above, from the viewpoint of reconciling the flexibility and neck toughness of the nonwoven fabric laminate, the nonwoven fabric laminate of the present disclosure is a spunbonded nonwoven fabric (crimped)/meltblown nonwoven fabric (ultrafine fiber)/spunbonded nonwoven fabric (crimped)/spun The structure of the bond nonwoven fabric (crimped) is more preferable.

(Manufacturing method of nonwoven fabric laminate)

There is no restriction|limiting in particular as a manufacturing method of a nonwoven fabric laminated body, A well-known method can be used.

For example, the nonwoven fabric manufacturing apparatus shown in FIG. 9 can be used.

The nonwoven fabric manufacturing apparatus includes extruders (1) and (1') for extruding the olefin-based polymer (A) and the olefin-based polymer (B), and a spinning spinneret (2) for spinning the extruded raw material into fibers (3) ), an ejector 5 that draws the fibers 3, a collector 6 that forms a nonwoven fabric 8 by collecting the fibers after stretching, and a bonding unit that heat-seals at least a part of the nonwoven fabric 8 (9) and a winder for winding the nonwoven fabric after thermal fusion. The collector device 6 is provided with a suction unit 7 for efficiently collecting fibers by suction, under the surface (collection surface) for collecting fibers. In this nonwoven fabric manufacturing apparatus, the fibers 3 obtained by the spinneret 2 are cooled by air for cooling the fibers (coated air).

Example

Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples unless departing from the gist thereof. In addition, unless there is a notice in particular, "part" is a mass basis.

In the present Example, the basis weight (g/m ² ) was measured by the following method.

Ten specimens of 100 mm (fiber flow direction: MD) x 100 mm (direction orthogonal to the fiber flow direction: CD) are taken from the nonwoven fabric to be measured. The sampling site of the test piece is set to 10 places along the CD direction. Next, the mass [g] of each sampled specimen is measured using an electronic balance (manufactured by Kensei Kogyo Co., Ltd.), and the average value of the mass of each specimen is calculated.

Converted to the mass [g] ^{per 1 m 2} from the average value obtained above, let ^{the basis weight [g/m 2} ] of each nonwoven fabric.

In this Example, the average fiber diameter is measured by the following method.

First, by using an electron microscope, the magnification is appropriately adjusted (for example, 200 times), a photograph of the fiber nonwoven fabric is taken, and among the fibers constituting the fiber nonwoven fabric, 50 arbitrary fibers are selected, and the width of the selected fiber ( diameter) is measured. And let the value calculated as the average value of the measured fiber widths (diameters) be the average fiber diameter.

On the other hand, the average fiber diameter of the ultrafine fibers (including meltblown fibers) is also measured by appropriately adjusting the magnification of the electron microscope (for example, 1,000 times) and using the above-described method for measuring the average fiber diameter.

Width retention is computed with the following method.

First, using a jig, the distance between the jigs is 350 mm, and the both ends of the longitudinal direction of the nonwoven fabric laminated body of width 200mm x length 450mm are pinched|interposed. Next, the nonwoven fabric laminate is set in a tensile tester and stretched with a tension of 100 N/m, and then the width is measured. And the width retention ratio is computed with the following formula.

Width retention (%) = (width at tension (mm) / initial width (mm)) x 100

<Evaluation>

Each of the following evaluations was performed about each Example and the comparative example, and each evaluation result was shown in Table 2.

(tensile strength)

About the nonwoven fabric laminated body, it measured based on JISL1906. From the nonwoven fabric laminate, a test piece having a width of 25 mm x a length of 200 mm was taken, using a tensile tester at a distance between chucks of 100 mm and a head speed of 100 mm/min, MD (fiber flow direction): 5 points, and CD (fiber flow direction) direction orthogonal to): Five points were measured, the average value was calculated, respectively, and the tensile strength (N/25mm) was calculated|required.

(water pressure resistance)

It carried out according to the water pressure resistance JIS L1072A method (low water pressure method). Take 4 specimens of about 15 × 15 cm, install them in a water resistance test device (manufactured by Tester Industry Co., Ltd.) so that the surface of the specimen comes into contact with water, and use a leveling device with room temperature water at 60±3 cm/min or 10± It was raised at a rate of 0.5 cm/min, water pressure was applied to the test piece, the water level when water leaked from three places on the opposite side of the test piece was measured, and the water pressure resistance was calculated from the pressure at that time.

(flexibility)

Based on JIS L1096, the so-called cantilever method evaluated the flexibility. Specifically, it was carried out by the following method.

1) The test piece 30 of 2 cm x 15 cm was prepared, and it left still on the test stand 40 as shown in FIG.

2) The test piece 30 was slowly extruded in the direction of the arrow, and the distance 50 moved until the test piece was bent was measured.

3) It measured about the case where the MD of a test piece was parallel to a movement direction, and the case where the CD of a test piece was parallel to a movement direction.

On the other hand, the higher the numerical value measured above, the better the rigidity of the nonwoven fabric laminate, and the lower the value, the better the flexibility of the nonwoven fabric laminate.

(Neck-in coefficient)

As an index of neck toughness, the width retention was measured by the method previously described, and using the measured width retention ratio, the neck-in coefficient was calculated as a value calculated by the ^{width retention (%) / basis weight (g/m 2 ).}

On the other hand, the higher the neck-in coefficient, the better the neck toughness.

(radioactive)

In each Example or Comparative Example, the number of times of yarn cutting when the polymer constituting each layer was spun was measured and evaluated according to the following evaluation criteria.

A: No yarn cutting

B: Thread cutting occurred more than once.

(Formability)

Embossing WHEREIN: The embossing roll was made to run for 5 minutes, the adhesion state which arises when a nonwoven fabric laminated body passes through the embossing roll was confirmed, and it evaluated according to the following evaluation criteria.

A: The state in which adhesion is not confirmed at all with the naked eye.

B: A state in which adhesion is visually confirmed, or a state in which it is wound on an embossing roll

<Example 1>

(1st floor)

A nonwoven web formed from side-by-side crimped composite fibers (hereinafter referred to as "crimped composite fibers I") by performing composite melt spinning by a spunbonding method using the following IA component and the following IB component. was deposited on the moving collection surface to produce a first layer. In the crimped composite fiber I, the mass ratio of component IA/component IB was 40/60.

Table 1 shows the average fiber diameter of the crimped composite fiber I in the first layer and the basis weight in the first layer.

-Olefinic polymer of crimped composite fiber I (A) (component IA)-

Melting point 162° C., Mz/Mw 2.24, MFR: 60 g/10 min (Measured at a temperature of 230° C. and a load of 2,160 g according to ASTM D1238. Hereinafter, the same applies unless otherwise specified.) Propylene homopolymer (h-PP)

-Olefinic polymer of crimped composite fiber I (B) (IB component)-

Melting point 142°C, Mz/Mw 2.19, MFR 60 g/10 min Propylene/ethylene random copolymer (r-PP)

(2nd floor)

A second layer was produced on the nonwoven web of the first layer using the same method and components as those described for the first layer, thereby producing a nonwoven web having a laminate structure.

Table 1 shows the average fiber diameter of the crimped composite fiber I in the second layer and the basis weight in the second layer.

(3rd floor)

A propylene homopolymer having a melting point of 159° C. and an MFR of 850 g/10 min was fed to the die of the melt blown nonwoven fabric manufacturing apparatus, and from the die heated to the molding temperature shown in Table 1, a melt blown nozzle (diameter 0.32 mm, 41 hole/inch) ), discharged together with high-temperature and high-speed air at the molding temperature shown in Table 1 blown from both sides of the nozzle using the Fibers I) were deposited in-line on the nonwoven webs of the first and second layers to produce a third layer, thereby producing a laminated nonwoven web.

Table 1 shows the average fiber diameter of the non-crimped composite fiber I in the third layer and the basis weight in the third layer.

(4th floor)

A fourth layer was produced on the nonwoven web of the third layer using the same method and components as those described for the first layer, thereby producing a nonwoven web of a laminate structure.

Table 1 shows the average fiber diameter of the crimped composite fiber I in the fourth layer and the basis weight in the fourth layer.

Then, the nonwoven web of the laminated structure was heat-sealed by the following embossing rolls under the following embossing conditions to obtain an SSMS nonwoven fabric laminate. The embossing area ratio of the crimping|compression-bonding part was 11 %. In addition, the total basis weight of the whole nonwoven fabric laminated body is shown in Table 1.

-Embossing Roll-

Embossing area rate: 11%

Embossing Aspect Ratio: 4.1mm/mm ²

Rockwell hardness of embossed substrate: 37HRC

-Embossing Conditions-

Embossing Temperature: 142℃

Embossing line pressure: 784N/cm

<Example 2, Example 3, Comparative Example 1, and Comparative Example 2>

The average fiber diameter of the first layer, the second layer and the fourth layer was adjusted as shown in Table 1, the average fiber diameter of the third layer was adjusted as shown in Table 1, and the basis weight of the first layer to the fourth layer was adjusted as shown in Table 1 Except having changed as described in Example 1, it carried out similarly to Example 1, and obtained the SSMS nonwoven fabric laminated body which has the total basis weight shown in Table 1.

<Comparative example 3>

(1st floor)

The 1st layer was produced using the method similar to the method described in the term of (1st layer) of Example 1.

Table 1 shows the average fiber diameter of the crimped composite fiber I in the first layer and the basis weight in the first layer.

(2nd floor)

A nonwoven web formed from side-by-side crimped composite fibers (hereinafter referred to as "crimped conjugated fibers II") by performing composite melt spinning by a spunbonding method using the following IIA component and the following IIB component. was deposited in-line on the nonwoven web of the first layer to produce a second layer, thereby producing a laminated nonwoven web. In the crimped composite fiber II, the mass ratio of IIA component/IIB component was 40/60.

Table 1 shows the average fiber diameter of the crimped composite fiber II in the second layer and the basis weight in the second layer.

-Olefin polymer of crimped composite fiber II (A) (component IIA)-

A mixture (propylene/ethylene random copolymer/propylene homopolymer) in which the mass ratio (propylene/ethylene random copolymer/propylene homopolymer) of a propylene/ethylene random copolymer having a melting point of 142°C and an MFR of 60 g/10 min and a propylene homopolymer having a melting point of 162°C and an MFR of 3 g/10 min is 96 to 4 ( Mz/Mw 2.54).

-Olefin polymer of crimped composite fiber II (B) (IIB component)-

Melting point 142°C, Mz/Mw 2.19, MFR 60 g/10 min Propylene/ethylene random copolymer

(3rd floor)

A third layer was produced using the same method as the method described in the section (3rd layer) of Example 1, except that the molding temperature was set to the temperature shown in Table 1 and the DCD was set to the DCD shown in Table 1. .

Table 1 shows the average fiber diameter of the non-crimped composite fiber I in the third layer and the basis weight in the third layer.

(4th floor)

A fourth layer was produced on the nonwoven web of the third layer using the same method and components as those described for the second layer, thereby producing a nonwoven web of a laminate structure.

Table 1 shows the average fiber diameter of the crimped composite fiber II in the fourth layer and the basis weight in the fourth layer.

Then, under the same method and embossing conditions as in Example 1, the laminated nonwoven web was heat-sealed with an embossing roll to obtain an SSMS nonwoven fabric laminate. The embossing area ratio of the crimping|compression-bonding part was 11 %. In addition, the total basis weight of the whole nonwoven fabric laminated body is shown in Table 1.

<Comparative Example 4 and Comparative Example 5>

The average fiber diameter of the first layer, the second layer and the fourth layer was adjusted as shown in Table 1, the average fiber diameter of the third layer was adjusted as shown in Table 1, and the basis weight of the first layer to the fourth layer was adjusted as shown in Table 1 Except having changed as described in, it carried out similarly to Comparative Example 3, and obtained the SSMS nonwoven fabric laminated body which has the total basis weight shown in Table 1.

<Comparative Example 6 and Comparative Example 7>

The average fiber diameter of the first layer, the second layer and the fourth layer was adjusted as shown in Table 1, the basis weight of the first layer, the second layer and the fourth layer was changed as described in Table 1, and the third layer was Except not having produced, it carried out similarly to Comparative Example 3, and obtained the nonwoven fabric laminated body which has the total basis weight of Table 1.

As shown in Table 2, a nonwoven fabric layer A (first, second and fourth layers) comprising crimped composite fibers and a nonwoven fabric layer B (third layer) comprising ultrafine fibers having an average fiber diameter of less than 1.35 μm are provided. and Examples 1 to 3, in which the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate was 2.0% to 8.0%, was excellent in flexibility and neck toughness.

On the other hand, in Comparative Example 1, in which the ratio of the basis weight of the nonwoven fabric layer B (third layer) to the total basis weight of the nonwoven fabric laminate was more than 8.0%, the cantilever value was high and the flexibility was inferior.

In Comparative Example 2, in which the ratio of the basis weight of the nonwoven fabric layer B (third layer) to the total basis weight of the nonwoven fabric laminate was less than 2.0%, the value of the neck-in coefficient was low, and the neck toughness was inferior.

With respect to Comparative Examples 3 to 5 in which the average fiber diameter of the ultrafine fibers in the nonwoven fabric layer B was 1.35 µm or more, Comparative Examples 3 and 5 were inferior in both flexibility and neck toughness, and Comparative Example 4 was inferior in neck toughness.

With respect to Comparative Examples 6 and 7, which did not include the nonwoven fabric layer B containing ultrafine fibers having an average fiber diameter of less than 1.35 μm, Comparative Example 6 was inferior in neck toughness, and Comparative Example 7 was able to collect a nonwoven fabric laminate. there was no

As for the indication of Japanese Patent Application No. 2019-061595 for which it applied on March 27, 2019, the whole is taken in into this specification by reference.

All documents, patent applications, and technical standards described in this specification are hereby incorporated by reference to the same extent as if each individual document, patent application, and technical specification were specifically and individually recorded to be incorporated by reference. do.

Claims (10)

A nonwoven layer A comprising crimped composite fibers, and
A nonwoven fabric layer B comprising ultrafine fibers having an average fiber diameter of less than 1.35 μm is provided;
A nonwoven fabric laminate wherein the ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 2.0% to 8.0%. The method of claim 1,
The nonwoven fabric laminate having an average fiber diameter of the ultrafine fibers of 1.00 µm or more and less than 1.35 µm. 3. The method according to claim 1 or 2,
A nonwoven fabric laminate wherein a ratio of the basis weight of the nonwoven fabric layer B to the total basis weight of the nonwoven fabric laminate is 5.0% to 8.0%. 4. The method according to any one of claims 1 to 3,
The nonwoven layer A is a layer of spunbond nonwoven,
The nonwoven fabric layer B is a layer of melt blown nonwoven fabric. 5. The method according to any one of claims 1 to 4,
The crimped conjugated fiber has at least two regions: (a) composed of the olefin-based polymer (A) and (b) composed of the olefin-based polymer (B);
The mass ratio [(a):(b)] of the part (a) and the part (b) is 10:90 to 60:40,
The melting point of the olefin-based polymer (A) is higher than the melting point of the olefin-based polymer (B), and the Mz/Mw of the olefin-based polymer (A) is larger than the Mz/Mw of the olefin-based polymer (B). The nonwoven fabric laminated body which satisfies at least one. 6. The method of claim 5,
The said olefin-type polymer (A) and the said olefin-type polymer (B) are a propylene-type polymer, The nonwoven fabric laminated body. 7. The method according to claim 5 or 6,
The said crimped composite fiber is a nonwoven fabric laminated body which has an eccentric core-sheath structure in which the said (a) part is a core part (a'), and the said (b) part is a sheath part (b'). 8. The method according to any one of claims 1 to 7,
A nonwoven fabric laminated body heat-sealed by embossing. 9. The method of claim 8,
The nonwoven fabric laminate whose embossing area ratio by the said embossing is 5 % - 20 %. A hygiene product having the nonwoven fabric laminate according to any one of claims 1 to 9.

Images